B How exactly do SMBHs in the center of galaxies form

[ebos]

Oh yeah, correction. I meant to say SgrA* instead of mangling it by saying Sag* but I know you understood what I meant. It isn't easy getting old.

 

[newjerseyrunner]

You have to remember that the universe was much much denser in the distant past when most of these monsters formed. Through telescopes, astronomers can see objects called quasars which are in the process of forming galaxies. They are some of the most violent objects in the universe.

 

[looking4sophia]

""Centrally symmetric mass distribution cannot emit gravity waves even when changing.
The asymmetry of a Binary black hole Merging is what produces changing quadrupole moment and allows emission of gravity waves.""
quoted from above.

The rapidly spinning and orbiting Binary BHs were descibed as Dumbell shaped
before they merged into a single spherical BH in a matter of minutes.

Is this dumbell shape with a highly dynamic concave and convex surfaces
what you consider Asymmetric enough to produce a Gravity Wave??

This Asymmetry only existed for a short time and might explain the short duration
of the Gravity Wave event.

 

[|Glitch|]

Astronomers find evidence for 'direct collapse' black hole

Astronomers Aaron Smith and Volker Bromm of The University of Texas at Austin, working with Avi Loeb of the Harvard-Smithsonian Center for Astrophysics, have discovered evidence for an unusual kind of black hole born extremely early in the universe. They showed that a recently discovered unusual source of intense radiation is likely powered by a "direct-collapse black hole," a type of object predicted by theorists more than a decade ago. Their work is published today in the journal Monthly Notices of the Royal Astronomical Society.

Source: Astronomers find evidence for 'direct collapse' black hole - Royal Astronomical Society

It would appear that if the temperature is hot enough to ionize hellium (>100,000°K) and there is an extremely strong UV source, which could have only existed in the very early universe, the Eddington Limit does not apply. Allowing for the collapse of gas directly into a super massive black hole, and thus kick-starting the formation of galaxies in the early universe. In the current universe (z < 6) such a direct collapse scenario would only be possible in Population III star clusters with >100,000°K black body temperatures or in the presence of a super massive black hole with a non-thermal Compton-thick spectrum. In other words, a direct collapse super massive black hole is not very likely to occur today.

See Also:
Evidence for a direct collapse black hole in the Lyman-alpha source CR7 - arXiv 1602.07639

 

[phinds]

Right now there is a medium sized black hole orbiting the SMBH at the Milky Way's center.

I can't say for sure that that's wrong, but it seems unlikely since the orbits of the stars closest to the SMBH have been mapped in some detail and I do not recall that including any evidence that they were being perturbed by a much more massive object other than the SMBH itself. Of course, that would depend somewhat on what you mean by "medium sized". If it's something only a modest number of solar masses then it might not show up.

 

[PeterDonis]

Centrally symmetric mass distribution cannot emit gravity waves even when changing.

This is true, but no real collapse process will be exactly spherically symmetric. If it's not, it could have a time-varying quadrupole moment and emit gravitational waves.

 

[ebos]

When I posted this I had just read an article from a team actually studying our black hole After posting my comment I went back and for the life of me cannot find the page. Apologies but the woman in charge seemed quite optimistic. Next time I will start a better system for saving these articles better in order to provide the link.